Chance of Dying From Backscatter Radiation Same as Chance of Terrorism • Hacker News Board

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#121

Post by fexl » Fri, Nov 19, 2010, 1:46 AM UTC

stcredzero wrote: post #96

aphyr wrote: post #18

Actual web page: http://www.public.asu.edu/~atppr/bodyscan.html Actual article: https://docs.google.com/viewer?url=http://www.public.asu.edu... The first thing you'll learn in radiation safety is that the nature of the dose matters a lot. Sometimes you're A-OK if you can survive the initial dose. Other doses are accumulative. It depends on the energy of the radiation, the tissue's scattering cross-section, the time,…

George Bush International doesn't have this yet. I'm going to opt out of scanning for my flight back from Pittsburgh, however.

I'll be opting out as well, karma be damned.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#122

Post by Female » Fri, Nov 19, 2010, 1:49 AM UTC

Groxx wrote: post #113

lukeqsee wrote: post #110

Earlier quoted context omitted.

The accomplishment is amazing. I guess our country really still does care about liberty and -- imagine this -- the constitution. Trouble is, are people going to do anything with their "spitting mad[ness]?" I hope they do.

I think they just have an irrational fear of radiation outside the doctor's office (whether or not that's valid here) - due to it being crammed down their throats for decades - and a massive aversion to being seen naked - also largely due to it being crammed down their throats for decades. If they like liberty, why did/do they not get as spitting mad about the Patriot Act, the DMCA, and the ACTA? I'm guessing it's be…

Upvoted you, but I would like to add that I'm spitting mad and not afraid of radiation or being naked. I think at least part of it is simply mass hysteria. It's very easy when other people are upset to get swept up into it.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#123

Post by [deleted] » Fri, Nov 19, 2010, 1:52 AM UTC

Female wrote: post #122

Groxx wrote: post #113

Earlier quoted context omitted.

I think they just have an irrational fear of radiation outside the doctor's office (whether or not that's valid here) - due to it being crammed down their throats for decades - and a massive aversion to being seen naked - also largely due to it being crammed down their throats for decades. If they like liberty, why did/do they not get as spitting mad about the Patriot Act, the DMCA, and the ACTA? I'm guessing it's be…

Upvoted you, but I would like to add that I'm spitting mad and not afraid of radiation or being naked. I think at least part of it is simply mass hysteria. It's very easy when other people are upset to get swept up into it.

[deleted]

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#124

Post by tibbon » Fri, Nov 19, 2010, 2:24 AM UTC

BCM43 wrote: post #51

tibbon wrote: post #24

Earlier quoted context omitted.

Two things have made the US safer 1- Pilots with guns & keeping the doors closed for the full flight 2- Passengers not willing to allow others on the plane do harm to the plane. If passengers see things happen now, they will stand up and makes attempts to stop them. We won't have a 9/11 style hijacking. Even if someone gets a box cutter in, people will take them down before they'll let them take the plane. I can't im…

What we are trying to stop has shifted from someone hijacking the plane to someone trying to blow it up. However, this is not a new threat at all, and there are always more ways of getting a bomb on the plane as well as more targets.

Perhaps, but why do we still focus then so much on 'hijacking' items, like knitting needles that would do little good in making bombs? We haven't reverted to pre 9/11 search coverage of hijack items. Actually, we haven't backed down at all on anything.

It seems that once something is identified a threat, it will always now be seen as a threat.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#125

Post by tibbon » Fri, Nov 19, 2010, 2:29 AM UTC

davidj wrote: post #94

tibbon wrote: post #24

Earlier quoted context omitted.

Two things have made the US safer 1- Pilots with guns & keeping the doors closed for the full flight 2- Passengers not willing to allow others on the plane do harm to the plane. If passengers see things happen now, they will stand up and makes attempts to stop them. We won't have a 9/11 style hijacking. Even if someone gets a box cutter in, people will take them down before they'll let them take the plane. I can't im…

won't work. Flight 93 was taken back by the passengers and Bush ordered it to be shot down anyway. http://www.youtube.com/watch?v=3V9MD15qs5s http://www.abovetopsecret.com/forum/thread624915/pg1

I don't think we'll ever have a good idea about what happened with flight 93. If the plane was 100% under control and in communication with other planes/ground control, it wouldn't have been shot down.

But the real point is that now no one would allow a few guys with boxcutters to take over the plane in the first place. They aren't getting in the cockpit, because that isn't going to open in almost any circumstance.

I know if I see some guy stand up and start threatening the plane, I will do whatever it takes to disarm and disable them with what I have available on me- even if I am outmatched physically by size or weaponry. I'd feel certain that if other passengers think that someone is going to take over the plane, they will help out.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#126

Post by electromagnetic » Fri, Nov 19, 2010, 2:36 AM UTC

jerf wrote: post #53

josefresco wrote: post #44

Earlier quoted context omitted.

Terrorism can in both small and very large ways effect entire nations. backscatter radiation? Not so much. It's illogical to compare the two and make judgments on based solely on the death rate. You don't need to kill people (all of them) to influence them.

Erosion of civil liberties can in both very small and very large ways affect entire nations. I'm actually way more worried about that, and I think that's the rational answer. (Edit: Implicit in the way I phrased that, BTW, and I'm now making explicit, is that I agree you have a good point and you shouldn't have been downmodded. I believe the secondary effects of civil liberties erosion outweigh the secondary effects…

When essentially the entire country is united except the political forefront, the effects have reached the entire nation. Once the government gets too distanced from the populace, it loses relevance and becomes the enemy.

How many violations before the populace decides on another Tea Party?

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#127

Post by RK » Fri, Nov 19, 2010, 2:49 AM UTC

butterfi wrote: post #28

With all due respect to Dr. Reiz, and the Dept. of Physics at ASU, I think I'll be taking my advice from the group of doctors from UCSF (a school well known and respected for its medical research) who wrote a formal letter to the president's science advisor. The letter is worth reading. "Agard and several of his UCSF colleagues recently wrote a letter to John Holdren the president's science adviser, asking for a more…

This part of their letter doesn't make sense:

Unlike other scanners, these new devices operate at relatively low beam energies (28keV). The majority of their energy is delivered to the skin and the underlying tissue. Thus, while the dose would be safe if it were distributed throughout the volume of the entire body, the dose to the skin may be dangerously high.

The main issue is that the limit for a smaller volume of the body is actually greater than the body as a whole. Radiation dose is somewhat similar to a density, in that it's measured in energy deposited per mass. Your body is better at dealing with a high dose in a small volume, than it is with a low dose in a large volume.

...these new airport scanners are largely depositing their energy into the skin and immediately adjacent tissue, and since this is such a small fraction of body weight/vol, possibly by one to two orders of magnitude, the real dose to the skin is now high.

This statement doesn't make sense either. Dose is J/kg, so the fact that the volume (read mass) is small is taken into account.

This part sounds the most interesting:

In addition, it appears that real independent safety data do not exist. A search, ultimately finding top FDA radiation physics staff, suggests that the relevant radiation quantity, the Flux [photons per unit area and time (because this is a scanning device)] has not been characterized. Instead an indirect test (Air Kerma) was made that emphasized the whole body exposure value, and thus it appears that the danger is low when compared to cosmic rays during airplane travel and a chest X-ray dose.

The problem with this statement is that Air Kerma is the quantity that you'd use to calculate the dose. It is only measured indirectly in the sense that you can set the detector to have the conversion coefficients built in (you actually measure the quantity Exposure).

It seems that the letter was probably written by people with concern, but not expertise. I just know enough to see some problems.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#128

Post by machrider » Fri, Nov 19, 2010, 3:02 AM UTC

wvenable wrote: post #42

cedsav wrote: post #33

1 in 30M? so, with over 600M passengers per year, that's roughly 20 people a year who would get cancer (and die?) because of those machines. I'm not sure how credible are those stats, but I wouldn't want to be making decisions at the TSA right now...

Not everyone gets screened. So only a fraction of those 600M passengers are getting a dose.

The plan is that all 2200 checkpoints in the USA will have backscatter or millimeter wave scanners within 2 years.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#129

Post by nubian » Fri, Nov 19, 2010, 3:13 AM UTC

uvdiv wrote: post #101

aphyr wrote: post #18

Actual web page: http://www.public.asu.edu/~atppr/bodyscan.html Actual article: https://docs.google.com/viewer?url=http://www.public.asu.edu... The first thing you'll learn in radiation safety is that the nature of the dose matters a lot. Sometimes you're A-OK if you can survive the initial dose. Other doses are accumulative. It depends on the energy of the radiation, the tissue's scattering cross-section, the time,…

This is a grossly irresponsible abuse of statistics. What's even stranger is that the author agrees . In his paper (conclusions, page 15): > The major public health effect of concern at low doses of ionizing radiation is cancer. There is clear evidence of cancer induction at effective dose above about 200 mSv. Below an effective dose of about 100 mSv radiogenic cancer mortality risk estimates for all cancers is highl…

> Use of collective dose to estimate public health impacts when large populations are exposed to trivial doses is inappropriate and not reasonable.

First, let's make sure we are clear about the difference between collective (for a population) and cumulative (adding up repeated doses for an individual).

Second, "inappropriate" and "not reasonable" tend to be weasel words with regard to scientific findings. The real issue is that the effects of small doses haven't been rigorously studied, unlike with high doses.

Rather than actually study them, we see brusque dismissals.

Re: Chance of Dying From Backscatter Radiation Same as Chance of Terrorism

#130

Post by nubian » Fri, Nov 19, 2010, 3:21 AM UTC

uvdiv wrote: post #109

aphyr wrote: post #21

Earlier quoted context omitted.

This comparison is meaningless. The risk of cancer is caused by DNA errors. Your cells are constantly checking and repairing your DNA for mutations and damage. They can usually repair or detect a low error rate, like the kind you get from living at high altitude, in a house with a minor radon source, or flying on a plane. What they can't deal with as well is a sudden burst of many errors. Backscatter X-ray scanners d…

> What they can't deal with as well is a sudden burst of many errors. Actually that is false, as far as low doses: > When you are asked whether there is a critical time period over which 1 rem of dose may have a greater biological impact than it might otherwise have, the answer is "No." One rem of dose is sufficiently low that whether it was delivered within one second or spread over a year or more, we would not expe…

Let me quote from your own source:

"There have been numerous biological experiments conducted, with nonhuman organisms, that demonstrate that the rate at which radiation dose is delivered can affect the extent of biological response. Thus a sufficiently high dose delivered over a period of a few minutes may be expected to have a greater biological impact than the same dose spread over a year."

The only question is what constitutes a "sufficiently high" dose, due to extrapolation. See 5).

THEIR OWN POSITION PAPER on backscatter scanners recommends per-screening and per-year (time limit!) maximums FAR below the threshold that they claimed wasn't a problem in the first place -- see 8).

4) Further, the terse "no" answer looked disingenuous. The cited position paper link was broken but I tracked it down.

It appears to be "Radiation Risk in Perspective", PS010-2 (which I assume is the updated version of PS010-1).

It has nothing to say about doses over short time periods.

http://www.hps.org/hpspublications/positionstatements.html

5) The issue seems to be that there is very little data about low-dose exposures, so regulations are based on extrapolation from high-dose exposures.

See http://www.ncrponline.org/PDFs/TST_NRC%20_04-08-08.pdf (third slide)

6) What it does say is this:

"the Health Physics Society recommends against quantitative estimation of health risks below an individual dose of 5 rem in one year or a lifetime dose of 10 rem above that received from natural sources."

7) The whole point of their objection was that we lack the empirical evidence to extrapolate from high doses to low doses. Then the article you cite does exactly that. They go from saying, "we lack proof that the answer is X" to saying, "the answer is ~X".

8) The recommended standard "limits the reference effective dose delivered to the subject to 0.25 microsieverts (25 microrem) per screening. Additionally, a screening facility should not expose any individual to more than 250 microsieverts (25 millirem) reference effective dose in a year."

"Use of Ionizing Radiation for Security Screening Individuals" PS017-1

http://www.hps.org/hpspublications/positionstatements.html

How they can go from saying in the first paper, "However, below 5–10 rem (which includes occupational and environmental exposures), risks of health effects are either too small to be observed or are nonexistent" to supporting a maximum of 0.025 rem per year is entirely unclear.

Except that the Health Physics Society seems to have turned into a pro-industry spokesgroup.

The current president works for Dade Moeller, who are embroiled in a number of controversies, to put it lightly.

A lot of extremely damaging information is cited in the original link below.

""Hirsch then zeroed in on Dade Moeller’s radiation plan and on the controversial company itself, whose namesake testified back in the 1990s that money spent on cleaning up Cold War-era nuclear facilities was being wasted since there would be a cure for cancer."

Original comment:

http://news.ycombinator.com/item?id=1889673